With the advent of consumer audio and video products that employ sophisticated digital processing techniques, it has become increasingly necessary to find ways to exploit the full potential of digital technology as applied to broadcast video, audio and other data oriented products. If we consider such sources of video and audio information as broadcast television stations, satellite broadcast, cable TV, videotapes and digital disks, increasingly such information is represented in a fashion suitable for manipulation by automated electronic hardware such as computers or decoders. For example, the direct video broadcast (DVD) standards address digital broadcasting from a satellite's terrestrial stations and cable TV systems. Even analog broadcasts such as normal NTSC (National Television Standards Committee) broadcasts from local stations may be captured and digitized. It is of course highly desirable to be able to store, reposition and selectively play back any of this broadcast data.
A device which performs some of these functions that all consumers are familiar with is the videocassette recorder (VCR) which uses magnetic tape to store the information. The inherently linear nature of tape leads to functions such as rewind, fast forward and pause. However, a VCR cannot both capture and play back information at the same time. Further, the quality on the tape storage medium is never especially high; and it tends to deteriorate fairly rapidly both with time and/or with repeated playing. However, VHS tapes do have the advantages of being easily transported, stored, moved from one machine to another, and used for rerecording.
Therefore, it would be highly desirable to provide these advantages in a storage device which has higher capacity and is capable of directly storing digital data. Further it would be very desirable to provide similar transportability and access to other forms of digital and analog data.